Creating a Software RAID Partition

EnGarde Secure Linux allows the creation of Software RAID partitions. A Redundant Array of Inexpensive Disks (RAID) allows redundancy and performance over multiple hard disks. RAID is usually done by a physical hardware controller or controlled by software. If a hardware RAID controller is found in the EnGarde system Software RAID will not be an available option at installation time.

RAID has multiple configurations referred to as levels. EnGarde supports RAID levels 1 and 5.

RAID 1

A RAID 1 array consists of two hard disks and no limit on spares. This RAID level is sometimes referred to as ``mirroring''. It makes a mirror image of the first drive on the remaining drives. If the first drive fails a backup is used. The size of a RAID 1 partition is limited to the size of the smallest partition in the array.

RAID 5

A RAID 5 array consists of at least three disks and no limit on spares. RAID 1 offers larger partition sizes than RAID 5 with increased read performance but slightly reduced write performance over RAID 1. RAID 5 stores parity information across all disks for redundancy making it possible to recover from a failed disk. The size of a RAID 5 partition is determined by taking the total number of disks in the array minus one and multiplying that by the size of the smallest partition in the array.

RAID Spares

In the event of disk failure the Software RAID system will reconstruct the RAID array using the parity information contained on its RAID disks. It will write the reconstructed data to one of the spare disks in the system. The spare disk remains unused until an error occurs. This method is sometimes refered to as ``hot reconstruction''. A RAID array can be fully reconstructed and operational with no system downtime.

If at least two disks are found in the EnGarde system a prompt to choose RAID 1 or No RAID will be given. Additionally, if three or more disks are present in the system an option for RAID 5 will be listed as well.

• [NOTE:]Once a Software RAID partition is created the entire system will be configured for Software RAID. Non-RAID partitions can not be created at that point.